Feature ids (by default all features are processed)Example: 1,3,7-9,13

output=name

Name for output vector map

option=string[required]

Action to be doneOptions: add, del, chlayer, sum, report, print, layers, transferadd: add a category to features without category in the given layerdel: delete category (cat=-1 to delete all categories of given layer)chlayer: change layer number (e.g. layer=3,1 changes layer 3 to layer 1)sum: add the value specified by cat option to the current category valuereport: print report (statistics), in shell style: layer type count min maxprint: print category values, layers are separated by ’|’, more cats in the same layer are separated by ’/’layers: print only layer numberstransfer: copy values from one layer to another (e.g. layer=1,2,3 copies values from layer 1 to layer 2 and 3)

v.category attaches, copies, deletes or reports categories of vector geometry objects. Further on, v.category adds a number given by the cat option to categories of the selected layer. These categories (IDs) are used to assign IDs or to group geometry objects into categories (several different geometry objects share the same category). These categories are also used to link geometry object(s) to attribute records (from an attribute table linked to vector map).

The type parameter specifies the type of geometry objects to which the category is added; it is similar to an input filter - only the geometry specified in ’type’ is processed.

If the type parameter is set to centroid and the option parameter set to add, new categories will be added to existing centroids. Note however, that new centroids cannot be created this way. To do so, they must be added manually using wxGUI vector digitizer or by running v.category with the type parameter set to area.

If categories are copied with option=transfer, a warning is issued if categories already exit in the layer they are copied to. In this case the user must make sure beforehand that copying categories from one layer to another layer does not cause undesired grouping of different geometry objects into the same categories. This can be avoided by specifying only one layer. The module will then find the next free layer number and copy categories to there. The new layer number is reported at the end.

Areas are a special case because it is impossible to attach a cat to an area without a centroid; in this case, the module places new centroids in areas automatically.

The cat parameter is only used with option=add, option=sum and option=del.

Categories can be deleted for the given layer with option=del. If cat is set to -1, all categories for the given layer are deleted. If cat is zero or positive, only this category value will be deleted. By default, cat is set to 1 which means that only categories of value 1 will be deleted.

The ids parameter specifies the list of feature IDs to which the operation is performed; by default, all vector feature ids are processed. The feature ID is an internal (unique) geometry ID that all vector primitives possess, and is separate from any category the feature may also possess. Use